Vortex flowmeter

Overview

A vortex flowmeter is a flow meter that uses piezoelectric crystals as detection elements and outputs a standard signal proportional to the flow rate. This instrument can be directly paired with instruments, or used in conjunction with computers and distributed systems to measure flow parameters of different media. This instrument is based on the detection principle of fluid vortex street, and its piezoelectric crystal for detecting vortex street does not come into contact with the medium. The instrument has the characteristics of simple structure, good universality, and high stability

Vortex flowmeter can be used for flow detection and measurement of various gases, liquids, and vapors.

The vortex flowmeter can be used in conjunction with the intelligent flow integrator produced by our company, as well as with intelligent instruments produced by other instrument manufacturers, and has strong universality.

Two working principles

The basic principle of a vortex flowmeter is the Karman vortex principle, which states that the separation frequency of vortices in the vortex is proportional to the flow velocity.

The diameter of the flow meter body is basically the same as the nominal diameter of the instrument. As shown in Figure 1, there is an approximately isosceles triangle shaped cylinder inserted into the flow body, with its axis perpendicular to the direction of the measured medium flow and its bottom facing the fluid.

When the measured medium flows through the cylinder, vortices are alternately generated on both sides of the cylinder, and the vortices are continuously generated and separated. Two rows of staggered vortices are formed downstream of the cylinder, known as "vortex streets". Theoretical analysis and experiments have shown that the frequency of vortex separation is directly proportional to the flow velocity of the column side medium.

In the formula:

F - frequency of vortex separation on the cylinder side (Hz);

V - Column side flow velocity (m/s);

D - width of the upstream face of the column (m);

Sr - Strouhal number. It is a constant that depends on the cross-sectional shape of the cylinder and is essentially independent of fluid properties and flow velocity.

Three product features

The sensor measuring probe is packaged with special technology and can withstand high temperatures up to 350 ℃

Sensitive components are sealed inside the probe body, and the detection components do not come into contact with the measuring medium, resulting in a long service life

The sensor adopts compensation design to improve the seismic resistance of the instrument

Simple structure, no moving parts, high durability

Within the specified Reynolds number range, the measurement is not affected by the temperature, pressure, or viscosity of the medium

Flow meters can be applied in explosion-proof situations with good safety

Wide range ratio, up to 10:1 15:1

Strong universality, capable of measuring unclean gases and liquids

Four technical parameters

Environmental temperature: (-40-55) ℃;

Relative humidity: (5-90)%;

Atmospheric pressure: (86-106) Kpa

Nominal diameter: (15-1500) mm (insert structure if larger than 200mm);

Measurement medium: liquid, gas, steam;

Nominal pressure: 1.6Mpa, 2.5Mpa, 4.0Mpa

Medium temperature: (-40~+350) ℃;

Accuracy level: 0.5 level, 1.0 level, 1.5 level, 2.5 level;

Linearity: ≤± 1.5%;

Repeatability: ≤ 0.5%, ≤ 1.0%;

Output signal: voltage pulse;

(4-20) mA DC (two-wire system);;

Power supply: Voltage pulse 12V DC or 24V DC;

Current type 24V DC

Intelligent current type 24V DC

Intelligent battery type 3.6V DC

Load resistance: The maximum load resistance shall not exceed 350 Ω.

Body material: 304 stainless steel

Connection method: (15-300) mm flange clamp structure;

(200-1500) mm is an insertable structure;

Protection level: IP65, IP67;

Cable interface: PG10

Explosion proof type: intrinsic safety type; Explosion proof type

Explosion proof mark: ia Ⅱ CT6; dIIBT4